Process for increasing the yield of lower boiling hydrocarbons

ABSTRACT

A process for increasing the yield of lower boiling hydrocarbons from heavy hydrocarbon fractions by oxidizing a heavy hydrocarbon fraction using for example air followed by subjecting the oxidized heavy hydrocarbon fraction to both a pyrolysis step and hydrocracking step.

United States Patent Peck et a1.

[4 1 June 20, 1972 [S4] PROCESS FOR INCREASING THE YIELD OF LOWER BOILING HYDROCARBONS [72] lnventors: Reese A. Peck; Raymond F. Wilson, both of Fishkill, N .Y.

[73] Assignee: Texaco Inc., New York, N.Y.

[22] Filed: Nov. 13, 1970 [21] Appl. No.: 89,518

Related US. Application Data [63] Continuation-impart of Ser. No. 787,560, Dec. 27,

I968, abandoned.

208/85 51 1nt.Cl ..C10gl3/l2 [58] FieldofSearch ..208/3,5,7,8,68,85,49

Primary Examiner-Herbert Levine Attorney-Thomas H. Whaley, Carl G. Ries and Robert Knox, .lr.

[ 5 7] ABSTRACT A process for increasing the yield of lower boiling hydrocarbons from heavy hydrocarbon fractions by oxidizing a heavy hydrocarbon fraction using for example air followed by subjecting the oxidized heavy hydrocarbon fraction to both a pyrolysis step and hydrocracking step.

12 Claims, No Drawings PROCESS FOR INCREASING THE YIELD OF LOWER BOILING HYDROCARBONS This application is a continuation-in-part of our co-pending application Ser. No. 787,560 filed December 27, 1968 and now abandoned.

This invention relates to a process for increasing the yield of lower boiling hydrocarbons in a hydrocracking process and more particularly to a process wherein a heavy petroleum hydrocarbon fraction is oxidized, subjected to a pyrolysis step and then a hydrocracking step to produce said improved yield.

Generally, hydrocracking finds its highest degree of utility in the cracking of hydrocarbons boiling in the heavy naphtha and light and heavy gas oil ranges. It has however met with only limited acceptance in the upgrading of heavy hydrocarbon oils, i.e., those containing high boiling components having substantial sulfur and nitrogen contents such as whole crude oil, topped crudes and residua, shale oil, coal tars, etc. The various high molecular weight sulfur and nitrogen compounds present in such oils tend to poison the hydrocracking catalyst and to deposit coke thereon during the hydrocracking operation, whereas in thermal hydrocracking processes the yields of lower boiling hydrocarbons are small in comparison to processes utilizing a catalyst. It has been particularly found that the higher boiling petroleum fractions of such oils, i.e. those fractions boiling above about 750 F., and particularly above about 850 F., contain relatively high proportions of the above-mentioned objectionable contaminating materials. Accordingly, conventional hydrocracking of such fractions, or of oil feeds containing such fractions, has proved to be of very limited effectiveness.

It will be appreciated, therefore, that there is presently a high incentive for discovering a successful means for hydrocracking heavy hydrocarbon oil feeds containing high boiling petroleum fractions to valuable lower boiling products.

It is therefore an object of this invention to provide an improved process for hydrocracking such feeds whereby higher yields of lower boiling hydrocarbons are obtained.

It has now been found that improved yields of lower boiling hydrocarbons can be obtained from heavy hydrocarbon fractions through the use of a process which comprises l) oxidizing a heavy hydrocarbon fraction with an oxidant optionally in the presence of an oxidation promoting catalyst, (2) pyrolyzing the oxidized heavy hydrocarbon fraction from step 1, (3) hydrocracking the product from step 2 and (4) recovering lower boiling hydrocarbons.

The process of this invention is carried out by first contacting the heavy hydrocarbon fraction with an oxidizing amount of an oxidant optionally in the presence of an oxidation promoting catalyst for a time sufficient to effect oxidation of at least a part of the heavy hydrocarbon fraction. By the use of the term at least a part it is meant that oxidation step (1) produces increases in the combined oxygen content of the heavy hydrocarbon charge stock so that the resulting product has a combined oxygen content of from about 0.10 wt. to about l0.0 wt. more preferably from about 0.25 wt. to about 5.0 wt. In carrying out process step 1, an oxidant is utilized such as oxygen, ozone, organic peroxides, organic hydroperoxides, organic peracids, optionally in the presence of a catalyst.

The amount of oxidant used in process step 1 will depend upon the desired increase in oxygen content obtained during oxidation step 1, such as oxygen content increases set forth above. In general, air rates of from about 500 to 20,000 preferably from about 2,000 to 12,000 standard cubic feet (s.c.f.) per barrel of hydrocarbon charge stock are utilized and a liquid hourly space velocity (volume of feed per volume of catalyst per hour, L.H.S.V.) of from about 0.2 to about 10, more preferably from about 0.5 to about 6. In the case of ozone, organic peroxides, organic hydroperoxides and organic peracids a concentration of oxidant generally within the range of from about 1.0 to about moles of oxidant per mole of oxygen incorporated into the hydrocarbon material is utilized more preferably from about 1.5 to about 4 moles of oxidant. It is preferred to use an excess of air or the other types of oxidant above that needed to incorporate the actual number of moles of oxygen (representing the oxygen increase) into the hydrocarbon charge stock, preferably from about 5 to about 500 wt. excess oxidant. The preferred oxidant in process step 1 is oxygen (preferably as air). When a catalyst is employed, it is preferred to use a catalyst concentration varying from about 0.0001 to about 10 wt. based upon the weight of the heavy hydrocarbon fraction, still more preferably from about 0.10 to about 10 wt. the catalyst being used at a concentration which is sufiicient to promote the effectiveness of the oxidant.

The temperature utilized in carrying out oxidation step 1 can vary over a wide range and in general a temperature of from about F. to about 600 F. is utilized, depending upon the oxidant. In general a time within the range of from about 15 minutes to about 24 hours preferably from about one-half hour to about 20 hours is utilized in process step 1 In the case of a gas as an oxidant, the time can vary over a wide range depending upon the particular amount of gas such as oxygen or ozone which is passed into the reaction mixture. In general for the oxidation step 1 utilizing oxygen, a temperature within the range of from about 100 F. to about 600 F. preferably within the range of from about 200 F. to about 400 F. is utilized. When ozone is utilized, a low temperature such as from 20 F. to about F. can be used. The number of moles of oxidant utilized can be obtained during the time utilized for the oxidant contact step. The oxidation step 1 in general is carried out at from atmospheric pressure to about 20 atmospheres although pressures above 20 atmospheres for example up to about 100 atmospheres can be utilized.

The hydrocarbon material from process step 1 is then pyrolized generally at a temperature of from about 500 F. to about l,500 F. preferably from about 500 F. to about 1,000 E; pressures of from about 0 to about 500 p.s.i.g. preferably 0 to about 100 p.s.i.g.; and a period of time in hours from about 0.2 to about 10 more preferably from about 0.5 to about 5 In addition the pyrolysis step may be carried out in the presence of an inert gas, for example nitrogen. In general during the pyrolysis step the amount of oxygen in contact with the hydrocarbon material is maintained at a low level, e.g. the inert gas should be substantially free of oxygen and pyrolysis step 2 should be carried out under an atmosphere which is essentially oxygen-free.

The hydrocarbon material from pyrolysis step 2 is then hydrocracked under hydrocracking conditions such that hydrogenation and cracking of the hydrocarbon material takes place. The conversion, expressed as volume percent conversion to products boiling below about 430 R, will generally be maintained above aBout 20 percent more preferably above about 40 percent. Hydrocracking step 3 can be either a thermal or catalytic hydrocracking step and can in addition be combined with pyrolysis step 2. Thus, for example, a gas such as hydrogen can be utilized in place of an inert gas under pyrolysis conditions as set forth above, or modified conditions such as hydrocracking pressures in the presence of a hydrocracking catalyst. in general however, it is preferred to carry out pyrolysis step 2 separately, followed by hydrocracking step 3.

Thus conditions that are utilized in hydrocracking step 3 are in general temperatures of from about 550 F. to about 850 F., preferably 675 to 775 F.; pressures of from about 500 to about 3,000 p.s.i.g. preferably 1,000 to 2,000 p.s.i.g., liquid hourly space velocities of from about 0.1 to about 10, preferably 0.5 to 2.5, volumes of feed per volume of catalyst per hour; and hydrogen rates of from about 2,000 to about 20,000 preferably 6,000 to 12,000, standard cubic feet (s.c.f.) per barrel of feed.

The recovery of lower boiling hydrocarbons is readily accomplished by removing lower boiling hydrocarbons which vaporize under hydrocracking conditions and recovering the liquid lower boiling hydrocarbons by means of cooling and condensation of the hydrocarbon vapors from the hydrocracking unit.

The organic oxidants include by way of example hydrocarbon peroxides, hydroperoxides and hydrocarbon peracids wherein the hydrocarbon radicals in general contain from about one to about 30 carbon atoms per linkage. With respect to the hydrocarbon peroxides and hydrocarbon hydroperoxides, it is particularly preferred that such hydrocarbon radical contain from four to 30 carbon atoms per peroxide linkage and more particularly from four to 16 carbon atoms per peroxide linkage. With respect to the hydrocarbon peracids the hydrocarbon radical which is attached to the carbonyl carbon in general contains from one to about 12 carbon atoms more preferably from about one to about eight carbon atoms. It is intended that the term organic peracid includes by way of definition performic acid.

In addition, it is contemplated within the scope of this invention that the organic oxidants can be prepared in situ, that is the peroxides. hydroperoxides or peracids can be generated in the heavy hydrocarbon fraction and such organic oxidant is contemplated for use within the scope of this invention.

Typical examples of hydrocarbon radicals are alkyl such as methyl, ethyl, butyl, t-butyl, 3-methyl-l-pentyl, n-octyl and those aliphatic radicals which represent the hydrocarbon portion of a middle distillate or kerosene, cycloalkyl radicals such as cyclopentyl, alkylated cycloalkyl radicals such as mono and polymethylcyclopentyl radicals, aryl and cycloalkyl substituted alkyl radicals such as phenyl and alkylphenyl substituted alkyl radicals examples of which are benzyl, methylbenzyl, capryl-benzyl, phenylethyl, phenylpropyl, naphthylmethyl, naphthylethyl, aryl radicals such as phenyl, and naphthyl, alkaryl radicals such as xylyl, alkylphenyl and ethylphenyl.

Typical examples of oxidants are hydroxyheptyl peroxide, cyclohexanone peroxide, t-butyl peracetate, di-tbutyl diterphthalate, t-butyl hydroperoxide, di-t-butyl peroxide, p-

menthane hydroperoxide, 2,5-dimethylhexane-2,5- dihydroperoxide and cumene hydroperoxide, organic peracids, such as perfonnic acid, peracetic acid,

trichloroperacetic acid, perbenzoic acid, and perphthalic acid and the like.

The catalysts which can be utilized in oxidant contact step 1 vary with the particular oxidant, the particularly preferred catalysts for use with air being potassium sulfate promoted vanadium oxide on alumina, vanadium oxide plus molybdenum oxide on alumina promoted with magnesium oxide, aluminum vanadate, vanadium oxide such as when prepared by hydrolysis of butyl vanadate with water in the presence of a porous catalyst carrier, silver oxide, copper oxide, vanadium oxide and stannic oxide on pumice, and tin vanadate on asbestos. Examples of catalysts which can be utilized with ozone, organic peroxides, organic hydroperoxides and organic peracids are metals such as titanium, zirconium, vanadium, tantalum, chromium, molybdenum and tungsten, the most preferred catalyst metals being titanium, vanadium, and molybdenum. These catalysts may be incorporated into the oxidation system by any means known to those skilled in the art either as a homogeneous or heterogeneous catalyst system. The catalyst can be incorporated by a variety of means and by the use of a variety of carriers. The particular catalyst carrier which is utilized is not critical with respect to the practice of this invention and can be for example, a support medium or an anion (including complex formation) which is attached to the metal (e.g. a ligand). Illustrative ligands include halides, organic acids, alcoholates, mercaptides, sulfonates and phenolates. These metals may be also bound by a variety of complexing agents including acetyl acetonates, amines, ammonia, carbon monoxide and olefins, amongst others. The metals may also be introduced in the form of organometallics including ferrocene" type structures. The various ligands illustrated above which are utilized solely as carriers to incorporate the metal into the process system, in general have an organic radical attached to-a functional group, such as the oxygen atom of carbonyloxy group of the acid, the oxygen of the alcohol, the sulfurof the mercaptan, the

of the sulfonate, the oxygen of the phenolic compound and the nitrogen of the amines. The organic radical attached to the aforedescribed functional groups can be defined as a hydrocarbon radical and in general can contain from one to about 30 carbon atoms. Typical examples of hydrocarbon radicals are set forth above.

The metals contained on the heterogeneous catalyst can include individual or combinations of metals. These metals can be distended on a suitable material, for example, alumina, silica (or combinations of both) as well as activated clays or carbon, amongst others. The modes of contacting whereby the catalytic effect may be achieved may include slurry-bed reactions or continuous contacting with a fixed bed of particulate catalyst through which the reactants may pass upwardly or downwardly on a fluidized catalyst bed.

The hydrocracking catalyst which can be utilized for the conversion of the hydrocarbon material from process step 2 may comprise for example a crystalline alumino-silicate zeolite, having a platinum group metal (e.g. platinum or palladium) deposited thereon or composited therewith. These crystalline zeolites are characterized by their highly ordered crystalline structure and unifonnly dimensioned pores, and have an alumino-silicate anionic cage structure wherein alumina and silica tetra-hedra are intimately connected to each other so as to provide a large number of active sites, with the uniform pore openings facilitating entry of certain molecular structures. It has been found that crystalline alumino-silicate zeolites, having a pore size of about 6 to 15, preferably 8 to 15 angstrom units, such as zeolite Y, when composited with the platinum group metal, and particularly after decationization to reduce the alkali metal oxide content of the zeolite to less than about 10 wt. preferably less than 1.0 wt. are effective hydrocracking catalysts, particularly for the hydrocarbon materials herein contemplated.

Advantageously, the alkali metal content of the zeolite is reduced by washing the zeolite several times with an aqueous solution of an ammonium salt, e.g., the chloride, drying at about 200300 F. and calcining the zeolite at a temperature not less than 800 F. and not more than 1,200 F. and then subjecting the calcined zeolite to additional ion exchange with an aqueous solution of the ammonium salt, and repeating the drying and calcining. By proceeding in this manner, the alkali metal content of the zeolite can be reduced to about 2-4 weight percent by the first ion exchange and to less than 1 weight percent by the second ion exchange.

Alternatively, the catalyst may comprise a Group VIII metal of the Periodic Table, such as nickel, cobalt, iron or one of the platinum group metals such as palladium, platinum, iridium, or ruthenium on a suitable support. Generally, it is preferred that an oxide or sulfide of a Group VIII metal (particularly iron, cobalt or nickel) be present in mixture with an oxide or sulfide of a Group Vl-B metal (preferably molybdenum or tungsten). Suitable carriers or supports include supports such as silica, alumina, magnesia, titania, zirconia and mixtures thereof; acidic clays; fluorided alumina; and mixtures of inorganic oxides, such as alumina, silica, zirconia, and titania in further admixture with decationized (hydrogen form) zeolites having uniform pore openings of 6-15 angstrom units. The hydrogenating component may be deposited or impregnated on the support in any manner well known in the art. If desired, the catalyst may be reduced, oxidized or sulfided prior to use.

A wide variety of heavy hydrocarbon fractions and/or distillates can be used as starting reactants in the process of this invention. Such heavy hydrocarbon fractions include full boiling range crude oils, topped or reduced crude oils, atmospheric and vacuum distillates, vacuum tower bottoms, visbreaker bottoms product, heavy cycle stock from thermal or catalytically-cracked charge stocks, etc. Particularly preferred heavy hydrocarbon fractions which can be utilized in the process of this invention are the atmospheric and vacuum distillates and deasphalted atmospheric and vacuum tower residues which have been topped to temperatures of at least 500 F. at atmospheric pressure.

The present invention can be carried out in batch, continuous, or semi-continuous operating cycles and in one or more actual or theoretical stages employing contacting and separation equipment conventionally employed in hydrocracking of petroleum stocks. In addition, a multi-stage mode of operation, that is a repeating of the process several times, can be utilized in carrying out the process of this invention.

The invention can be better appreciated by the following non-limiting examples.

In the following examples, a distillate stock was utilized as the hydrocarbon charge stock. The stock had the following properties.

Gravity, APl 60F. 27.6

Carbon Residue, Wt. 0.02

Sulfur, Wt. 0.49

Total Nitrogen, Wt. 0.10

ASTM Dist, vol.

lBP-5% 450/488F. /20 504/520F. 30/40 532/542F. 50 552F. 60/70 563/576F. 80/90 592/6l6F. 95/EP 636/662F.

EXAMPLE 1 To a reactor equipped with heating means and inlet and exit tubes is charged the distillate stock. During the continuous oxidation of the distillate stock over glass beads, a temperature of 400 F., an air pressure of 14.7 p.s.i.g., a liquid hourly space velocity (L.H.S.V.) of 1.0 and an air rate of 6,000 s.c.f.b. is maintained. The oxidized stock is charged to a reactor loaded with glass beads and pyrolized at a temperature of 700 F. at atmospheric pressure and a liquid hourly space velocity of 1 (basis volume of glass beads). The material after pyrolysis is charged to a reactor loaded with a catalyst containing 8 percent nickel and percent tungsten as the sulfides deposited on a support containing 58 percent silica, 22 percent alumina and 20 percent zeolite Y having an alkali metal content of 0.5 wt. The material is continuously hydrocracked at a temperature of 700 F., a pressure of 1,500 p.s.i.g. a L.H.S.V. of 1, and a hydrogen rate of 6,000 s.c.f.b. Over a 36 hour period a product is produced having an A.P.l. gravity up to 68.5.

EXAMPLE 2 To a reactor equipped with heating means and inlet and exit tubes and containing a potassium sulfate promoted vanadium oxide on alumina catalyst the distillate stock is charged. During the continuous oxidation of the distillate stock over the vanadium catalyst a temperature of 400 F., an air pressure of 14.7 p.s.i.g., a liquid hourly space velocity (L.H.S.V.) of 1.0 and an air rate of 6.000 s.c.f.b. is maintained. The oxidized stock is charged to a reactor loaded with glass beads and pyrolized at a temperature of 700 F. at atmospheric pressure and a liquid hourly space velocity of 1.2 (basis volume of glass beads). The material after pyrolysis is charged to a reactor containing the same hydrocracking catalyst as Example 1. The material is continuously hydrocracked at a temperature of 700 F., a pressure of 1,500 p.s.i.g. a L.H.S.V. of 1, and a hydrogen rate of 6,000 s.c.f.b.

EXAMPLE 3 To a reactor equipped with heating means and inlet and exit tubes is charged the distillate stock. During the continuous oxidation of the distillate stock over glass beads, a temperature of 400 F., an air pressure of 14.7 p.s.i.g., a liquid hourly space velocity (L.H.S.V.) of 1.0 and an air rate of 6,000 s.c.f.b is maintained. The oxidized stock is charged to a reactor loaded with glass beads and pyrolized at a temperature of 700 F. at atmospheric pressure and a liquid hourly space velocity of 1 (basis volume of glass beads). The material after pyrolysis is charged to a reactor containing a catalyst having 0.5 wt. palladium deposited on a support composed of 58 percent silica, 22 percent alumina and 20 percent decationized zeolite Y. The material is continuously hydrocracked at a temperature of 700 F., a pressure of 1,500 p.s.i.g., a L.H.S.V. of l and a hydrogen rate of 6,000 s.c.f.b.

EXAMPLE 4 To a reactor equipped with heating means and inlet and exit tubes and containing a silver oxide on alumina oxidation catalyst is charged the distillate stock. During the continuous oxidation of the distillate stock over the silver oxide catalyst a temperature of 400 F., an air pressure of 14.7 p.s.i.g., a liquid hourly space velocity (L.H.S.V.) of 1.0 and an air rate of 6,000 s.c.f.b. is maintained. The oxidized stock is charged to a reactor loaded with glass beads and pyrolized at a temperature of 700 F. at atmospheric pressure and a liquid hourly space velocity of 1.5 (basis volume of glass beads). The material after pyrolysis is charged to a reactor containing the same hydrocracking catalyst as Example 1. The material is continuously hydrocracked at a temperature of 700 F a pressure of 1,500 p.s.i.g. a L.H.S.V. of l, and a hydrogen rate of 6,000 s.c.f.b.

EXAMPLE 5 To a reactor equipped with heating means and inlet and exit tubes and containing a copper-chromium on alumina oxidation catalyst is charged the distillate stock. During the continuous oxidation of the distillate stock over the catalyst, a temperature of 350 F., an air pressure of 14.7 p.s.i.g., a liquid hourly space velocity (L.H.S.V.) of 1.0 and an air rate of 5,000 s.c.f.b. is maintained. The oxidized stock is charged to a reactor loaded with glass beads and pyrolized at a temperature of 800 F. at atmospheric pressure and a liquid hourly space velocity of 1 (basis volume of glass beads). The material after pyrolysis is charged to a reactor containing the same hydrocracking catalyst as Example 3. The material is continuously hydrocracked at a temperature of 750 F., a pressure of 1,500 p.s.i.g. a L.H.S.V. of 1, and a hydrogen rate of 6,000 s.c.f.b.

EXAMPLE 6 The distillate stock is charged to a reactor and pyrolized over glass beads at a temperature of 700 F. at atmospheric pressure and a liquid hourly space velocity of 1 (basis volume of glass beads). The hydrocarbon material after pyrolysis is charged to a reactor containing the same hydrocracking catalyst as Example 1. The material is continuously hydrocracked at a temperature of 700 F., a pressure of 1,500 p.s.i.g., a L.H.S.V. of l, and a hydrogen rate of 6,000 s.c.f.b. Over a 36 hour period a product is produced having an A.P.l. gravity up to 50.4.

EXAMPLE 7 To a reactor equipped with heating means and gas inlet and exit tubes is charged a distillate stock and a copper oxide on alumina catalyst. During the continuous oxidation of the distillate stock over the catalyst, a temperature of 400 F., an air pressure of 14.7 p.s.i.g., a liquid hourly space velocity (L.H.S.V.) of 1.0 and an air rate of 6,000 s.c.f.b. is maintained. The oxidized stock is charged to a reactor containing the same hydrocracking catalyst used in Example 1. The material is continuously hydrocracked at a temperature of 700 F., a pressure of 1,500 p.s.i.g. a L.H.S.V. of l, and a hydrogen rate of 6,000 s.c.f.b. Over a 36 hour period a product is produced having an A.P.l. gravity up to 55.4.

EXAMPLE 8 The distillate stock is charged to a reactor equipped with heating means and inlet and exit tubes and loaded with the hydrocracking catalyst used in Example l. The material is continuously hydrocracked at a temperature of 700 F., a pressure of l,500 p.s.i.g. a L.H.S.V. of l, and a hydrogen rate of 6,000 s.c.f.b. Over a 36 hour period a product is produced having an A.P.l. gravity up to 53.7.

The results in Examples 1, 6, 7 and 8 demonstrate the outstanding effectiveness of the process of this invention for increasing the yield of lower boiling hydrocarbons. More particularly a comparison between Example 1 (process of this invention) and Examples 6, 7 and 8 demonstrate that the combined oxidation pyrolysis and hydrocracking steps produce material having an A.P.l. gravity up to 68.5 whereas the use of either a pyrolysis and hydrocracking step, an oxidation and hydrocracking step or a hydrocracking step produces products having A.P.l. gravities of 50.4, 55.54, and 53,7, respectively. These results show that hydrocracking preceded by either oxidation or pyrolysis is essentially the same as hydrocracking alone but that hydrocracking preceded by oxidation and pyrolysis is vastly superior to either two-step combination. Thus, applicants have discovered that the use of a pyrolysis step together with an oxidation and hydrocracking step provides improved yields of lower boiling hydrocarbons greater than that obtained through the use of a single step or a combination of two steps.

While this invention has been described with respect to various specific examples and embodiments it is to be understood that the invention is not limited thereto and that it can be variously practiced within the scope of the following claims.

We claim:

1. A process for the production of lower boiling hydrocarbons which comprises oxidizing a heavy petroleum hydrocarbon fraction at a temperature between about 100 F. and 600 F. to produce a heavy petroleum fraction containing from about 0.l to 10.0 wt. combined oxygen, subjecting the partially oxidized fraction to pyrolysis by maintaining same at a temperature between about 500 F. and 1,500 P. for a period of time between 0.2 and 10 hours in an essentially oxygen free atmosphere, and contacting the pyrolyzed product with a hydrocracking catalyst under hydrocracking conditions.

2. The process of claim 1 in which the heavy petroleum fraction is oxidized by contact with air.

3. The process of claim 1 in which the oxidation is carried out in the presence of a catalyst.

4. The process of claim 3 in which the oxidation catalyst comprises vanadium.

5. The process of claim 3 in which the oxidation catalyst comprises copper.

6. The process of claim 1 in which the pyrolysis temperature is between 500 F. and l,000 F.

7. The process of claim 1 in which the time at pyrolysis temperature is between 0.5 and 5 hours.

8. The process of claim 1 in which the hydrocracking catalyst comprises a Group VIII metal on a support comprising a crystalline alumino-silicate zeolite having uniform pore openings of from 6-15 angstrom units and an alkali metal content of less than 1.0 weight 9. The process of claim 8 in which the Group VIII metal is palladium.v

10. The process of claim 8 in which the Group VIII metal is nickel.

11. The process of claim 1 in which the hydrocracking catalyst comprises nickel and tungsten on a support comprising a mixture of decationized zeolite Y, silica and alumina.

12. The process of claim 1 in which the hydrocracking catalyst comprises palladium on a support comprising a mixture of decationized zeolite Y, silica and alumina. 

2. The process of claim 1 in which the heavy petroleum fraction is oxidized by contact with air.
 3. The process of claim 1 in which the oxidation is carried out in the presence of a catalyst.
 4. The process of claim 3 in which the oxidation catalyst comprises vanadium.
 5. The process of claim 3 in which the oxidation catalyst comprises copper.
 6. The process of claim 1 in which the pyrolysis temperature is between 500* F. and 1,000* F.
 7. The process of claim 1 in which the time at pyrolysis temperature is between 0.5 and 5 hours.
 8. The process of claim 1 in which the hydrocracking catalyst comprises a Group VIII metal on a support comprising a crystalline alumino-silicate zeolite having uniform pore openings of from 6-15 angstrom units and an alkali metal content of less than 1.0 weight %.
 9. The process of claim 8 in which the Group VIII metal is palladium.
 10. The process of claim 8 in which the Group VIII metal is nickel.
 11. The process of claim 1 in which the hydrocracking catalyst comprises nickel and tungsten on a support comprising a mixture of decationized zeolite Y, silica and alumina.
 12. The process of claim 1 in which the hydrocracking catalyst comprises palladium on a support comprising a mixture of decationized zeolite Y, silica and alumina. 